Vehicle body and frame assembly including energy absorbing structure

ABSTRACT

A vehicle frame assembly has an energy absorbing structure including a first portion having a first generally uniform dimension. A second portion extends from the first portion and has a second generally uniform dimension that is greater than the first generally uniform dimension of the first portion, thereby defining a first shoulder between the first portion and the second portion. A third portion extends from the second portion and has a third generally uniform dimension that is less than the first generally uniform dimension of the first portion, thereby defining a second shoulder between the second portion and the third portion. The second portion has at least one stiffening rib formed therein. The third portion has at least one stiffening rib formed therein that is discontinuous with the stiffening rib formed in the second portion. The energy absorbing structure is adapted to be deformed during a collision such that the third portion is moved within the second portion to absorb energy.

BACKGROUND OF THE INVENTION

This invention relates in general to body and frame assemblies forvehicles. More specifically, this invention relates to an improvedstructure for such a vehicle body and frame assembly that includes astructure that is capable of absorbing energy in a controlled mannerduring a collision, thereby providing additional safety to the occupantsof the vehicle.

Many land vehicles in common use, such as automobiles, vans, and trucks,include a body and frame assembly that is supported upon a plurality ofground-engaging wheels by a resilient suspension system. The structuresof known body and frame assemblies can be divided into two generalcategories, namely, separate and unitized. In a typical separate bodyand frame assembly, the structural components of the body portion andthe frame portion of the vehicle are separate and independent from oneanother. When assembled, the frame portion of the assembly isresiliently supported upon the vehicle wheels by the suspension systemand serves as a platform upon which the body portion of the assembly andother components of the vehicle can be mounted. Separate body and frameassemblies of this general type are found in most older vehicles, butremain in common use today for many relatively large or specialized usemodern vehicles, such as large vans, sport utility vehicles, and trucks.In a typical unitized body and frame assembly, the structural componentsof the body portion and the frame portion are combined into an integralunit that is resiliently supported upon the vehicle wheels by thesuspension system. Unitized body and frame assemblies of this generaltype are found in many relatively small modern vehicles, such asautomobiles and minivans.

A recent trend in the development of passenger, sport utility, pickuptruck, and other vehicles has been to design the various components ofthe vehicle in such a manner as to absorb energy during a collision,thereby providing additional safety to the occupants of the vehicle. Asa part of this trend, it is known to design portions of the vehicle bodyand frame assembly so as to be at least partially collapsible during acollision so as to absorb to energy. To accomplish this, it is known toform such portions of the vehicle body and frame assembly to havecorrugated or similarly deformed shapes that are somewhat weaker thanthe other non-deformed portions of the vehicle body and frame assembly.During a collisions, such deformed portions are designed to be the firstportions of the vehicle body and frame assembly that are axiallycollapsed. Thus, the absorption of energy during a collision occurs in asomewhat controlled manner. A variety of such pre-deformed axiallycollapsible vehicle body and frame assembly structures are known in theart. Nonetheless, it would be desirable to provide an improved structurefor a vehicle body and frame assembly including a structure that iscapable of absorbing energy in a controlled manner during a collision,thereby providing additional safety to the occupants of the vehicle. Inparticular, it would also be desirable to provide such an energyabsorbing structure that is replaceable after a collision.

SUMMARY OF THE INVENTION

This invention relates to a vehicle frame assembly including a structurethat is capable of absorbing energy in a controlled manner during acollision, thereby providing additional safety to the occupants of thevehicle. The vehicle frame assembly can include a pair of longitudinallyextending side rails having a plurality of transverse cross membersextending therebetween. One or more energy absorbing structures can beprovided at the front end of each of the side rails or elsewhere on thevehicle frame assembly. In a first embodiment, the energy absorbingstructure includes a hollow nose cap that is secured to the front end ofthe side rail. The nose cap includes a first portion that is receivedtelescopically with the front end of the side rail and a second portionthat extends from the first portion. The second portion of the nose capis preferably formed integrally with the first portion and has an outersize that is larger than the outer size of the first portion so as todefine a first shoulder therebetween. The nose cap further includes athird portion that extends from the second portion and has an outer sizethat is somewhat smaller than the inner size of the second portion so asto define a second shoulder therebetween. If a relatively large force isexerted against the outermost end of the third portion of the nose cap,the second shoulder will bend, allowing the third portion of the nosecap to move telescopically inwardly relative to the second portion. Suchbending of the second shoulder and concurrent telescopic movement of thethird portion within the second portion absorbs energy from thecollision. In a second embodiment, the energy absorbing structureincludes a first portion that is formed integrally with the front end ofthe side rail and a second portion that extends therefrom. The secondportion is preferably formed having an outer size that is somewhatsmaller than the inner size of the first portion so as to define ashoulder therebetween. In a third embodiment, the energy absorbingstructure includes a first hollow member that is received telescopicallywith the front end of the side rail in engagement with one or moreinwardly extending first tabs formed thereon. Similarly, a second hollowmember is received telescopically with the first hollow member inengagement with one or more inwardly extending second tabs formedthereon. If a relatively large force is exerted against the outermostend of the second member, the tabs will bend, allowing the second memberto move telescopically inwardly relative lo the first member and thefirst member to move telescopically inwardly relative to the front endof the side rail. Such bending of the tabs and concurrent telescopicmovement of the members absorbs energy from the collision.

Various objects and advantages of this invention will become apparent tothose skilled in the art from the following detailed description of thepreferred embodiments, when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a vehicle frame assembly including afirst embodiment of an energy absorbing structure in accordance withthis invention.

FIG. 2 is an enlarged sectional elevational view of the first embodimentof the energy absorbing structure illustrated in FIG. 1 prior to beingaxially collapsed.

FIG. 3 is an enlarged sectional elevational view similar to FIG. 2showing the first embodiment of the energy absorbing structure afterbeing axially collapsed.

FIG. 4 is a perspective view of a vehicle frame assembly including asecond embodiment of an energy absorbing structure in accordance withthis invention.

FIG. 5 is an enlarged sectional elevational view of the secondembodiment of the energy absorbing structure illustrated in FIG. 5 priorto being axially collapsed.

FIG. 6 is a perspective view of a vehicle frame assembly including athird embodiment of an energy absorbing structure in accordance withthis invention.

FIG. 7 is an enlarged sectional elevational view of the third embodimentof the energy absorbing structure illustrated in FIG. 7 prior to beingaxially collapsed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, there is illustrated in FIG. 1 a portionof a first embodiment of a vehicle body frame assembly, indicatedgenerally at 10, in accordance with this invention. The vehicle frameassembly 10 is generally conventional in the art, and only thoseportions thereof that are necessary for a complete understanding of thisinvention will be described and illustrated. Furthermore, it will beappreciated that the illustrated vehicle frame assembly 10 is intendedto be representative of any conventional structure, separate orunitized, for a frame assembly for use in a vehicle. The illustratedvehicle frame assembly 10 is a ladder frame assembly including a pair oflongitudinally extending side rails 11 and 12 or similar structuralmembers having a plurality of transverse cross members 13, 14, 15, 16,and 17 extending therebetween. The side rails 11 and 12 extendlongitudinally throughout the entire length of the assembly 10 and aregenerally parallel to one another. Each of the side rails 11 and 12 inthe illustrated embodiment is formed from a single closed channelstructural member. However, it will be appreciated that one or both ofthe side rails 11 and 12 may be formed from a plurality of individuallyformed closed channel structural members that are secured together byany conventional means, such as by welding, riveting, bolting, and thelike. Furthermore, portions of the side rails 11 and 12 may be formedfrom open channel structural members if desired.

The cross members 13 through 17 extend generally perpendicular to theside rails 11 and 12 and may be formed having any conventionalstructure. The cross members 13 through 17 are spaced apart from oneanother along the length of the ladder frame assembly 10 and can besecured to the side rails 11 and 12 by any conventional means, such asby welding, riveting, bolting, and the like. When secured to the siderails 11 and 12, the cross members 13 through 17 provide lateral andtorsional rigidity to the ladder frame assembly 10. The structure of thevehicle body and frame assembly thus far described is conventional inthe art.

An energy absorbing structure, indicated generally at 20, is provided atthe front end of each of the side rails 11 and 12 of the vehicle bodyand frame assembly 10. However, it will be appreciated that the energyabsorbing structure 20 may be provided at any desired location on thevehicle body and frame assembly 10. The structure of one of the energyabsorbing structures 20 is illustrated in FIG. 2. As shown therein, theenergy absorbing structure 20 includes a hollow nose cap, indicatedgenerally at 21, that is secured to the front end of the side rail 11 ina conventional manner, such as by one or more welds 22. The illustratednose cap 21 is formed having a generally rectangular cross sectionalshape that corresponds with the cross sectional shape of the front endof the side rail 11. However, the nose cap 21 may be formed having anydesired cross sectional shape.

The nose cap 21 includes a first portion 23 that is receivedtelescopically with the front end of the side rail 11. Preferably, thefirst portion 23 is formed having an outer size that is only slightlysmaller than an inner size of the front end of the side rail 11. Thus,the first portion 23 of the nose cap 21 is received snugly within thefront end of the side rail 11. In this manner, the first portion 23 ofthe nose cap 21 can be mechanically supported within the front end ofthe side rail 11.

The nose cap 21 also includes a second portion 24 that extends from thefirst portion 23. The second portion 24 of the nose cap 21 is preferablyformed integrally with the first portion 23, although such is notnecessary. The second portion 24 of the nose cap 21 is preferably formedhaving an outer size that is larger than the outer size of the firstportion 23 so as to define a first shoulder 24 a therebetween, althoughsuch is not necessary. The first shoulder 24 a provides a structure forpositively positioning the nose cap 21 relative to the front end of theside rail 11 prior to securement thereto by the welds 22. The secondportion 24 of the nose cap 21 is preferably formed having an outer sizethat is approximately the same as or only slightly smaller that theouter size of the front end of the side rail 11. Thus, the outersurfaces of the nose cap 21 and the front end of the side rail 11 arepreferably substantially flush when secured together. If desired, one ormore embossed stiffening ribs 24 b may be formed in the second portion24 of the nose cap 21 for a purpose that will be described below.

The nose cap 21 further includes a third portion 25 that extends fromthe second portion 24. The third portion 25 of the nose cap 21 ispreferably formed integrally with the second portion 24, although suchis not necessary. The third portion 25 of the nose cap 21 is preferablyformed having an outer size that is somewhat smaller than the inner sizeof the second portion 24 so as to define a second shoulder 25 atherebetween. If desired, one or more embossed stiffening ribs 25 b maybe formed in the third portion 25 of the nose cap 21 for a purpose thatwill be described below.

FIG. 2 illustrates the energy absorbing structure 20 during normaloperation of the vehicle body and frame assembly 10. If the front end ofthe vehicle frame assembly 10 collides with an object at a relativelylow speed, a relatively small force will be exerted against theoutermost end of the third portion 25 of the nose cap 21. So long as themagnitude of such a relatively small force is not sufficient to overcomethe strength of the second shoulder 25 a, then the nose cap 21 willremain substantially as shown in FIG. 2.

However, if the front end of the vehicle frame assembly 10 collides withan object at a relatively high speed, a relatively large force will beexerted against the outermost end of the third portion 25 of the nosecap 21. The exertion of such a relatively large force causes the secondshoulder 25 a to bend, allowing the third portion 25 of the nose cap 21to move telescopically inwardly relative to the second portion 24, asshown in FIG. 3. Such bending of the second shoulder 25 a and concurrenttelescopic movement of the third portion 25 within the second portion 24absorbs energy from the collision. As a result, additional safety isprovided to the occupants of the vehicle. The stiffening ribs 24 b and25 b provided on the second and third portions 24 and 25 of the nose cap21 are provided to maintain the second and third portions 24 and 25 intheir original shapes during the collision. This is done to facilitatethe absorption of energy in a controlled manner during a collision.Because the nose cap 21 is formed as a separate piece from the side rail11, it can be removed from the side rail 11 with relative ease after acollision and replace with another non-deformed nose cap 21.

Referring now to FIGS. 4 and 5, there is illustrated a portion of asecond embodiment of a vehicle body frame assembly, indicated generallyat 10′, in accordance with this invention. The second embodiment of thevehicle frame assembly 10′ is generally the same as the first embodimentof the vehicle frame assembly 10 described above, and like referencenumbers are used to indicate similar structures. An energy absorbingstructure, indicated generally at 30, is provided at the front end ofeach of the side rails 11 and 12 of the vehicle body and frame assembly10′. However, it will be appreciated that the energy absorbing structure30 may be provided at any desired location on the vehicle body and frameassembly 10′. The structure of one of the energy absorbing structures 30is illustrated in FIG. 5. As shown therein, the energy absorbingstructure 30 includes a first portion 31 that is formed integrally withthe front end of the side rail 11. The illustrated first portion 31 isformed having a generally rectangular cross sectional shape thatcorresponds with the cross sectional shape of the front end of the siderail 11. However, the first portion 31 may be formed having any desiredcross sectional shape. The energy absorbing structure 30 also includes asecond portion 32 that extends from the first portion 31. The secondportion 32 is preferably formed integrally with the first portion 31,although such is not necessary. The second portion 32 is preferablyformed having an outer size that is somewhat smaller than the inner sizeof the first portion 31 so as to define a shoulder 32 a therebetween. Ifdesired, one or more embossed stiffening ribs 32 b may be formed in thesecond portion 32 of the energy absorbing structure 30. The energyabsorbing structure 30 functions in the same manner as the energyabsorbing structure 20 discussed above.

Referring now to FIGS. 6 and 7, there is illustrated a portion of athird embodiment of a vehicle body frame assembly, indicated generallyat 10″, in accordance with this invention. The third embodiment of thevehicle frame assembly 10″ is generally the same as the first embodimentof the vehicle frame assembly 10 described above, and like referencenumbers are used to indicate similar structures.

An energy absorbing structure, indicated generally at 40, is provided atthe front end of each of the side rails 11 and 12 of the vehicle bodyand frame assembly 10. However, it will be appreciated that the energyabsorbing structure 40 may be provided at any desired location on thevehicle body and frame assembly 10″. The structure of one of the energyabsorbing structures 40 is illustrated in FIG. 7. As shown therein, thefront end of the side rail 11 has at least one, and preferably aplurality, of tabs 11 a formed therein that extend inwardly into theinterior thereof. Such tabs 11 a can be formed in any conventionalmanner, such as by punching or cutting and bending. The purpose for suchtabs 11 a will be explained below.

The energy absorbing structure 40 includes a first hollow member 41 thatis secured to the front end of the side rail 11. The illustrated firstmember 41 is formed having a generally rectangular cross sectional shapethat corresponds with the cross sectional shape of the front end of theside rail 11. However, the first member 41 may be formed having anydesired cross sectional shape. If desired, an end 41 a of the firstmember 41 may be formed having a frusto-conical or otherwise reduceddimensional shape. The purpose for this reduced dimension end 41 a willbe explained below. The first member 41 is received telescopically withthe front end of the side rail 11 such that the reduced dimension end 41a of the first member 41 abuts the tabs 11 a extending within the siderail 11. Preferably, the first member 41 is formed having an outer sizethat is only slightly smaller than an inner size of the front end of theside rail 11. Thus, the first member 41 is received snugly within thefront end of the side rail 11. In this manner, the first member 41 canbe mechanically supported within the front end of the side rail 11. Thefirst member 41 can be secured to the front end of the side rail 11 byany conventional means, such as by one or more welds 41 b. The front endof the first member 41 has at least one, and preferably a plurality, oftabs 41 c formed therein that extend inwardly into the interior thereof.Such tabs 41 a can be formed in any conventional manner, such as bypunching or cutting and bending. The purpose for such tabs 41 a will beexplained below.

The energy absorbing structure 40 further includes a second hollowmember 42 that is secured to the front end of the first member 41. Theillustrated second member 42 is formed having a generally rectangularcross sectional shape that corresponds with the cross sectional shape ofthe first member 41. However, the second member 42 may be formed havingany desired cross sectional shape. If desired, an end 42 a of the secondmember 42 may be formed having a tapered or otherwise reduceddimensional shape. The purpose for this reduced dimension end 42 a willbe explained below. The second member 42 is received telescopically withthe front end of the first member 41 such that the reduced dimension end42 a of the second member 42 abuts the tabs 41 c extending within thefirst member 41. Preferably, the second member 42 is formed having anouter size that is only slightly smaller than an inner size of the firstmember 41. Thus, the second member 42 is received snugly within thefirst member 41. In this manner, the second member 42 can bemechanically supported within the front end of the side rail 11. Thesecond member 42 can be secured to the first member 41 by anyconventional means, such as by one or more welds 42 b.

FIG. 7 illustrates the energy absorbing structure 40 during normaloperation of the vehicle body and frame assembly 10″. If the front endof the vehicle frame assembly 10″ collides with an object at arelatively low speed, a relatively small force will be exerted againstthe outermost end of the second member 42. So long as the magnitude ofsuch a relatively small force is not sufficient to overcome the strengthof the tabs 11 a and 41 c, then the energy absorbing structure 40 willremain substantially as illustrated in FIG. 7.

However, if the front end of the vehicle frame assembly 10″ collideswith an object at a relatively high speed, a relatively large force willbe exerted against the outermost end of the second member 42. Theexertion of such a relatively large force causes the tabs 42 c to bend,allowing the second member 42 to move telescopically inwardly relativeto the first member 41. Such bending of the tabs 42 c and concurrenttelescopic movement of the second member 42 within the first member 41absorbs energy from the collision. In some instances, the exertion ofsuch a relatively large force also causes the tabs 11 a to bend,allowing the first member 41 to move telescopically inwardly relative tothe front end of the side rail 11. Such bending of the tabs 11 a andconcurrent telescopic movement of the first member 41 within the frontend of the side rail 11 absorbs additional energy from the collision. Asa result, additional safety is provided to the occupants of the vehicle.

Because the first and second members 41 and 42 are formed as separatepieces from the side rail 11, they can be removed from the side rail 11with relative ease after a collision and replace with anothernon-deformed nose cap 21. Furthermore, it will be appreciated that theenergy absorbing device 40 may include only one such member or three ormore of such members if desired. Although not illustrated in FIGS. 6 and7, either or both of the first and second members 41 and 42 may beformed having stiffening ribs for the same purpose as described above.

In accordance with the provisions of the patent statutes, the principleand mode of operation of this invention have been explained andillustrated in its preferred embodiment. However, it must be understoodthat this invention may be practiced otherwise than as specificallyexplained and illustrated without departing from its spirit or scope.

What is claimed is:
 1. A vehicle frame assembly comprising: a pluralityof structural members that are connected together to form a vehicleframe assembly, at least one of said structural members having a hollowportion; and an energy absorbing structure secured to said hollowportion of said one of said structural members, said energy absorbingstructure including: a first portion having a first generally uniformdimension, said first portion extending within said hollow portion ofsaid one of said structural members; a second portion extending fromsaid first portion and having a second generally uniform dimension thatis greater than said first generally uniform dimension of said firstportion so as to define a first shoulder between said first portion andsaid second portion that abuts said hollow portion of said one of saidstructural members; and a third portion extending from said secondportion and having a third generally uniform dimension that is less thansaid first generally uniform dimension of said first portion so as todefine a second shoulder between said second portion and said thirdportion; wherein said second portion has at least one stiffening ribformed therein and said third portion has at least one stiffening ribformed therein that is discontinuous with said stiffening rib formed insaid second portion; said energy absorbing structure adapted to bedeformed during a collision such that said third portion is moved withinsaid second portion to absorb energy.
 2. The vehicle frame assemblydefined in claim 1 wherein said one of said structural members and saidenergy absorbing structure are formed from metallic materials.
 3. Thevehicle frame assembly defined in claim 2 wherein said one of saidstructural members and said energy absorbing structure are securedtogether by welding.
 4. The vehicle frame assembly defined in claim 1wherein said second portion has a plurality of stiffening ribs formedtherein.
 5. The vehicle frame assembly defined in claim 1 wherein saidthird portion has a plurality of stiffening ribs formed therein.
 6. Thevehicle frame assembly defined in claim 1 wherein said second portionhas a plurality of stiffening ribs formed therein, and wherein saidthird portion has a plurality of stiffening ribs formed therein.
 7. Thevehicle frame assembly defined in claim 1 wherein a plurality of saidstructural members have respective hollow portions, and wherein anenergy absorbing structure is secured to each of said hollow portions ofsaid structural members.